- Antimicrobial agent isolated from Coptidis rhizome extract incubated with Rhodococcus sp. strain BD7100
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Coptidis rhizome (CR) is a widely used herbal medicine that contains protoberberine-type alkaloids. CR extract exhibits various pharmacologic activities. A previous study reported the isolation of Rhodococcus sp. strain BD7100 as a berberine (BBR)-utilizing bacterium, and the BBR-degradation pathway has been investigated. When we incubated strain BD7100 cells with CR extract, the number of viable cells declined with the degradation of components in the CR extract, and the culture broth exhibited antibacterial activity against strain BD7100. These results suggest that CR extract cultured in the presence of strain BD7100 contains one or more antibacterial agents. In this study, we isolated coptirhoquinone A (1) from CR extract incubated with strain BD7100 in Luria–Bertani (LB) medium, and the structure was elucidated using NMR and MS analysis. We also report the total synthesis and antimicrobial activities of 1 against bacteria, fungi, and Pythium sp.
- Ishikawa, Kazuki,Takahashi, Kazunori,Hosoi, Syun,Takeda, Hisashi,Yoshida, Hinaka,Wakana, Daigo,Tsubuki, Masayoshi,Sato, Fumihiko,Tojo, Motoaki,Hosoe, Tomoo
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- Divergent Total Syntheses of Flavonoid Natural Products Isolated from Rosa rugosa and Citrus unshiu
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The concise and step-economical total syntheses of three hydroxyaurones and one polymethoxyflavone from readily available starting materials is described. A divergent synthetic strategy is employed, which centres on a common chalcone scaffold from which both the aurone and flavone frameworks can be accessed through the use of different oxidative cyclisation methods. These are the first reported total syntheses of these biologically interesting compounds.
- Sum, Tze Jing,Sum, Tze Han,Galloway, Warren R. J. D.,Spring, David R.
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supporting information
p. 1725 - 1727
(2016/07/06)
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- The Baeyer-Villiger oxidation versus aromatic ring hydroxylation: Competing organic peracid oxidation mechanisms explored by multivariate modelling of designed multi-response experiments
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Peroxy acids can be used as the terminal oxidant for the Baeyer-Villiger oxidation of acetophenones and for direct ring hydroxylation of methoxy-substituted benzenes. An oxidative system involving 3-chloroperbenzoic acid (mCPBA) and 2,6-dimethoxyacetophenone as model substrate was investigated by means of statistical experimental design, multivariate modelling and response surface methodology. The outcome of the organic peracid oxidation experiments was portrayed by a multi-response matrix consisting of the yields of three different compounds; 2,6-dimethoxyphenyl acetate, 1-(4-hydroxy-2,6-dimethoxy-phenyl)ethanone and 3-hydroxy-2,6-dimethoxy-phenyl acetate. The optimized reaction protocol was utilized to investigate a series of various substituted acetophenones. The overall investigation revealed that both the molecular structure of the acetophenone substrate and the experimental conditions exhibited a substantial impact on whether the oxidation reaction follows the oxygen insertion or direct ring hydroxylation mechanism. An improved protocol for the direct ring hydroxylation was also obtained from the experimental and modelling described herein.
- Gambarotti, Cristian,Bj?rsvik, Hans-René
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p. 619 - 628
(2015/09/28)
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- A Concise Synthesis of Pyrazole Analogues of CombretastatinA1 as Potent Anti-Tubulin Agents
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CombretastatinA1 (CA1) binds to the β-subunit at the colchicine binding site of tubulin and inhibits polymerization. As such, it is both an antitumor agent and a vascular disrupting agent. It has been shown to be at least tenfold more potent than combreta
- Zaninetti, Roberta,Cortese, Salvatore V.,Aprile, Silvio,Massarotti, Alberto,Canonico, Pier Luigi,Sorba, Giovanni,Grosa, Giorgio,Genazzani, Armando A.,Pirali, Tracey
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supporting information
p. 633 - 643
(2013/08/22)
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- Synthesis of methoxy-substituted phenols by peracid oxidation of the aromatic ring
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A novel benign protocol for the preparation of hydroxy-methoxybenzene derivatives is disclosed. By utilizing this protocol, activated aromatic compounds such as l,3-dimethoxy-2-methyl-benzene and 1-(2,6-dimethoxyphenyl) ethanone are smoothly converted to the corresponding monohydroxylated compound. The reaction can be considered to be a normal aromatic electrophilic substitution reaction, and the regioselectivity for the reaction thus follows the similar rules as for electrophilic substitutions. The protocol is composed by benign reagents, namely, hydogenperoxide, acetic acid, and p-toluene sulfonic acid, which lead to the production of ethaneperoxoic acid in situ. The ethaneperoxoic acid operates as the hydroxylating reagent. The hydroxylation reaction is completed within a short period and requires moreover only mild experimental conditions, which make this novel protocol a green, cheap, and rapid process leading to hydroxy-methoxybenzene derivatives. The proposed reaction mechanism is supported by density functional theory and NMR spectroscopy experiments. The mechanism is constituted by two discrete steps: (a) addition of OH+ to the most nucleophilic carbon atom of the aromatic ring, which is the rate-determining step, and (b) the loss of the proton from the aromatic ring.
- Bjorsvik, Hans-Rene,Occhipinti, Giovanni,Gambarotti, Cristian,Cerasino, Leonardo,Jensen, Vidar R.
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p. 7290 - 7296
(2007/10/03)
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- SYNTHESIS OF NATURAL ISOFLAVANQUINONES BY THE OXIDATIVE REARRANGEMENT OF CHALCONES WITH THALLIUM(III) NITRATE: ABRUQUINONES A AND B
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The natural isoflavanquinones abruquinone A and B have been synthesized through the oxidative rearrangement of chalcones with Tl(NO3)3.The previously proposed structures are confirmed.
- Lupi, Alessandro,Marta, Maurizio,Lintas, Graziella,Marini Bettolo, Giovanni Battista
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p. 625 - 628
(2007/10/02)
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